SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '894c9c9367c0cbc08e7638b41d08a2f64182802dcb08e67eaecdc8009d2a2246' 
  AND token = 'y4ihBdLHDp/4Cr988pbAulb6txUXIIFGwNSMInMUkZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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