SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a37d0c55518b411855424fcb055bf986171f3ccaedd86a3d5a48da81394022cc' 
  AND token = 'zMi4Ch0nu7wSJq5vQ7LA4XqOb/288vrYIjtIgjvrR4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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