SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d2fbc6e25581868d75f7708aa8fcedd3e62a286e57dc1f9ca211a82475c3360' 
  AND token = 'GTnZEZndjYPvmvZozxGiThmlYFB7Fff3qAFxRxFWakM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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