SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4be623dfa9b173508895a36913c83266b70139882decc4b2c09c91c7b4234a09' 
  AND token = 'GoHu9zf2cjBSyvF3VZb0zU0LaNV+fjChx1YIqIvawqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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