SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e273085a56b1340cc10ba1bacdc82d0b0b902e8439de7be54a76e8a58d5e0390' 
  AND token = 'pLMgSUc1mXJCWqxfOYXCwvCb0BRGcZAvAK1SZgccOqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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