SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ec47d4fe223bc4b3c8a1a256dafbd3d95902f9d8df6a14197ab687bf3f51e24' 
  AND token = 'xKUGpkqEjBvxUpYOlvuI227ZaWqJtO2xCemXlHmnGg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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