SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f095a640813dd346a90f2a513eed50ce20e4a8598ec3959f4a64cce1de15369' 
  AND token = 'GrXWkhitytklcbP0oxMIUjuIh3FgKQxR47ltNbqQP+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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