SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64eb661bb08b56106731305adf8f89a774919cbe13620c1fb37d35f62c069a5a' 
  AND token = 'QFzFu8oMKT2my7WhuXFSEPsI2EdLE/pC+4tkAtxjw1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}