SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55aa6c9b333677516bb20b447fafc595fc67027d54bed5fe90475aaba2d20d2e' 
  AND token = 'lIijk5LTVpOI1MVka3ZMaqFd7HLdbUvXMqSpfaCg7jM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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