SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23b7f40255dfcf28e17422696a8f59e09615bf84118e846a781eb572d44cb2b9' 
  AND token = 'oTBDQTjDyxX/sUzLgzdXKBHbx18aNfZRaWjnxDcqrYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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