SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3251ff729c34698b1618191bbe4159ce81455afdd35e558d14bf82232f7c4619' 
  AND token = 'wJulzY4Iyt9d6FNbUdnSAYrk5dFdgsuZiY9iPPvwy08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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