SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eae357e387d8ef4b9e458833ee4d3f2a882cc69091a8e0a8fc7f70b82ce2e21f' 
  AND token = 'hUmyUvbWbcpnkLagk6E6dnQQzwykweTdYw9ADKaoATc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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