SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa127cb1b768bdd451df9a94681893b69f3997a2c267791f5fcd407e24a63c1d' 
  AND token = 'rSqe65OIOsdWuLcYkKKBCTth4b9A9gR1GEY4ihmW3o0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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