SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57b3fb4094b46e04fdc2bdd882d9187bd29b02aa955e385f18d8124a20aad79a' 
  AND token = 'm1FYcIuV0hKhOqGm7+jvZG+fQpfuezaWDH/D7Rjs73A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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