SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f381b72f84d90bfd4a3986800b71adc91a5bf959a02b1b0035f2e847557c31fb' 
  AND token = 'hpNRmZD6lwlKpXN8qtG83pzsRtStmVBNVfD1Gg+wPmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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