SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83595a8535ddcd0eef62f996d96af292d5340290342ce75fe3fde5d399cbd2c7' 
  AND token = 'B+F0XY4JC9LDkpmIxJm1cvwrNHZmQbB+8qgP8JC33pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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