SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7fb32b100847607cf7982a7ef1e73273636fb93dfd7afe24182cf7fa734b962' 
  AND token = 'xqwL2Mp2PadseAxz/MJXVGkKen022xaipVK/nd5yOCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}