SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b708aa8aba056f0a64ffcef4a23e58a7dc845630f6da773299b8c9664e6283ad' 
  AND token = 'dGqxAaw57UcQNoVN9sSpknwazujpIDe1BgyNOAFzM6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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