SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57d44884cdb49213cb75d8af1e0bc2b43efba41bf5d526285dd8c67caa924476' 
  AND token = '7b8xeGrEuaVkTPwYYyk/xt9wQPJGgtCGIzRnh+UqaW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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