SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3b0bffe850292fae759c7daefe30f0443d0912ff250b066c3feadedf1178f5ef' 
  AND token = 'fLYR73sY9Gcptuw11yT3Ai0VeZ7BwqV5M7pN3JDl9Ms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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