SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e942e3aec5498c246ad18791f11b6b1932e4d29bcfb60acc1b660ce07e3318f4' 
  AND token = 'AdDIededN9u5YDbd78OCuxFaTK0ji9JDAXzFNh+7XII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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