SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfdd12556465d59a7e9479e9d4731e6615d2929b5405aa50f3c7d566d4a47bb6' 
  AND token = '9lSUUediLzMAk1kl0l9p6XfoJLyjEg8fF+nW45CaCjs=' 
  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"
    }
  }
}