SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '915ae43138fb86c4928c8c723bc60030d1199ff4f87026eeed33318b3964c0de' 
  AND token = 'GYA4MEswOVSsjrBvE+uAaXDZ8nc4IQNplUyrI4IYrgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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