SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '285a6dbc539fda29617f28381424c084f6564a2e9ec2791cd32b5a789ab6edac' 
  AND token = 'rub3oPXyMYleVCrhCXtRhuYxNBkVqjsFV9Lp7PRmFBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}