SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7d18b2398ead5e8143292dcc639243ec2ca3072fc5647962b3e16fb64d311c7' 
  AND token = 'hj4pIMAQJvdIPXeeHclY5PWoQ5GudbyElKqv8f92ySw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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