SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc34b2739da4fe2178e16a5d57b153748d735e159029a2130df5ac4571d39a34' 
  AND token = 'rcIVvNhCYhYNH9GDcwJ0KY8ZDs+2gP8wqTpc6l91PqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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