SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84267f54ea1a40e3d66535aa9a2d4d1cbcded6e190b35947c2361482ac57a10c' 
  AND token = 'Zo/BBz1iV5KXe059qTpcX35OjU6M27Wi2niqKEeYaxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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