SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '529c99f76dee177fee30bfbaf3a340ef9fb84085e406a2d1a8e56eac603e1a89' 
  AND token = 'MpYdw3T8yFYiEpd83cu8TasPoMPprr4baWmmlZs68qE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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