SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0a664548a156db68787a90354e9775ccaf93cc2ff3347f83d70ba24be07a16a' 
  AND token = 'yrzte+FYCjJ6sATf3almx1HPWpdhLjLVBE3XmXKYAnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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