SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '90c7e4632133275648d09055cd7b9df73e5e4818439162a8ec74f653ccbcaf72' 
  AND token = '1pygEF59CpaeyPNCpc5BlLV6gdqgLzT1zca1IPWKHBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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