SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e753f2e1e727d8c1625b9f20d61ec955b228064d25b7d94cd6ddfa91321390d4' 
  AND token = 'QOHBwbStpVGGII1+KWRsujmy6Rwug+LSgTHuJLcinDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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