SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f5e1b00cfc9cdda76d33c7ccba24795a7c819c9bc02764373b9b202e202d253' 
  AND token = 'quGeltAvSGMsei44NfxcvZgTfjgLfeCtgXS7THknc9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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