SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b65743e3d6586bfa62f37e250f6c98cd5ad5c1d8ef1273c41a33f261830276fb' 
  AND token = 'Y7Jq0bqCpqR2ciGQ3UpgMJYPCZB7NfLh3gYjpjPsBas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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