SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9bd21b774394e8038e2b61dfb46a08c49b646136ec6012a67a75c84653218dd' 
  AND token = 'kBPLVDR0Oc3FP37+pqfVt/NXj5dwZ1p3ZuJgpndPlQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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