SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0536cb5e23b0cafa351ccbb038997139bfddc713bf91793ba59cea0b05c99290' 
  AND token = 'PBoIUvnPqVH/9AOpqqP5y+q95PfNWCjgsjUbodXkmmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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