SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4715403445e24fc65d8bc5a428d76e191d395c768ec95ad9c847a6ebe1791ef0' 
  AND token = 'UbXaoRKDv6nG4mXagQ5YjYFruVtKui+yRaM7zWNqqCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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