SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '91cd72537c27e4561db287dfb4763ba7098378276f95a08500fe748f507b4c7c' 
  AND token = 'uHgMXPv/cAvHJ/uDdEcnU/uF5VrvniRazoZdoTniBOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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