SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20d953ecfcddd18e3f9aa6e739199e0e9589ff4cc0be69a1a835b7bc0837937a' 
  AND token = 'cxgthnCTTmPk10LFvpDW/3DGTzw7QhnV4GZwo9jNtK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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