SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5623fec1524b3759087233cab293743af506285d09c07d9d043938f297c7089' 
  AND token = '0p4AfJcRgDly53FGaME4ZpTpc31y3JEzZIb73zzDw54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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