SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83795dbf11be48673cafdb431d78ef2a6b7b63a5fdb813bd10c39922f03be120' 
  AND token = 'pUH+O4niPixbT1x36dOWhusoQ7nrk1bKGuq4fJ8hN7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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