SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38f52a4cf31965eafb8075904f204b8abc92082ed70296fabeb8617671ef0d4a' 
  AND token = 'sU7hF5DPREfRK1A8ysV1rf1c2C7wkJu61miYy9IK7/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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