SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8af2860f6eb1314b3d130a069b5f0be10d71fda81f9523fe03f04402cfe4c60' 
  AND token = 'xaya+f+49OF3lq+iciv0dHGEFN0Ga9rZhHKyi1Ri7NI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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