SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '731e2b26198c279250331b80f0ccda1d86c2e617c8b7e35d8e44de696bfd3dd7' 
  AND token = 'QVhdgdG3t6SKP/zXj154vSOgPBkMaLWnUE9XvJ3LK90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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