SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c80fa600cc526766504f47f1c445f6fd8ac2a9b2f288d6b16cfe838f26c88956' 
  AND token = 'GReUbyoL92uWPSUMOZysOrQlrKhHIECspxMukXorS+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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