SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9643591584c3fc2dbdfd1ed7193e64ae55dec31fa561ad86279548da9f8779b4' 
  AND token = 'K+VEW1/oDimRzUkGtjh/Q886CNIYBeB0EApBXtXjB+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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