SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9afd3bb1b1b1c1de4229b4e48bc55fb2d17a1f7fb769284bbddc9dc350906510' 
  AND token = 'YIV/wcmYDGKquVukLbcUv6rMwSGrtVV+hkFE8g2W7h4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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