SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cfabce46c169340451d790062f91e432202c742d3431e38f29dc25101681202' 
  AND token = 'FOCCTYNXpzNW7vJvjvZuDWGoLL1mwAnZwt6yWqsKbOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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