SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76a63d13da28476cd19c4b977136e01aad24c17cbb9b3bd1c49b18093d74ee14' 
  AND token = 'vTqb91xMrIGgjB483cJPhr7SEJZe0YkfUZgtyuZpiQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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