SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59420decc08f5da0652953dfaeb042d1433a3558515b53009df08ffc76c39abe' 
  AND token = 'CrVO+YoHs+XYdA8upsDHbj05bJh16fOTBo7IB/JR7Bs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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