SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4608dddb0413c7e9daaa9d4ee1cbf88b8988dd8779a081c97244f52e52850b08' 
  AND token = 'lo520epKpnc3rNFcjO2ybDyLp/8qgEN1ydNpDKmjhnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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