SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0c795a8e64c0fc92b7cfaf5f9c5193be7c5c1d8e73d4345d754724a5c05c049' 
  AND token = 'xnvY4GGpaYPqCtx7HLy6+xRFEhc7jnwae8n+nXzd7jY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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