SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd84339124d87916346d6441418ce6255be8625e258403f30c41ff87ffe446a73' 
  AND token = 'RmwKVRgx/idYyKAVdTH7oDeN619ve9ntMv8o2cCfkL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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