SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '450ba8f7c01ef60dae3a572a1d96361feaf22dd93c14cde5abebddf855ee9ca8' 
  AND token = 'qZ1/BzDOrmL45kNi8oWwBUPEhKY8eBH0wOS0bYKq5cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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