SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fd765421c2cded77007c91bad907833bb6b4276021b2f3f1ff800ead849a2e4c' 
  AND token = 'Ed1+TDLeQI0ocxVfe9z+toh1e+u+Cl+aYkNKe4NwErE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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