SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8c7107688099ece376db3c9b816fd3f82c6b193a5b25093b540ea976028b3b9' 
  AND token = 'cEIX1BNnqYMoVmGrGOKusgYjd8QlcshBDN0namE2ygs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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