SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ce062435e0fa510d4c6b6127073dab2630cad8be916bba9898cf44421f5cf70' 
  AND token = 'junWhZ5CVMk03V8a+IKahHWfaxhOegVqp5uXwsTd3zA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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