SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51aa29d0c0d7cb8770d5e3fa1a2b66d6078b40726fd1ea6ed7800d557201f491' 
  AND token = '12kq61YR0EUZubd0/aWQLatbAkbEwCzK2BAwEPJwXbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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