SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6405d16dcf6d86245d0bd405584bf15f1c4fa4c14999964f296112ddfd583d8' 
  AND token = 'I+1hk/iatxhg6BJBoiWXITNTUSptzHB9mqEJ5HF+pc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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