SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e187f3ad0718a786b02db7fa4b971368be1595097153902c14a4d4754801beb3' 
  AND token = 'O0SClUD5lQSk/iitp4cglcxuxfbXM6eguqZpgk+9KRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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