SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dd716344d9e61fdb1bd2c3561e6a2a0520f0195407387789e22977d1a60b51e3' 
  AND token = 'dIJq/3dNIZ1jb3E3/Zg2KVHs4vZmZzmBmqP0jXhSLU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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