SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f78c2400df7fd16b1a0af0c850ac6f1436b8a03c0b12199b6fa900d44e75fe97' 
  AND token = 'xUsYMlYmTh5UND7GyLZVQ1433s11Eu9gjEO60qlXovw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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