SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f36ac6571086ff323c1de91034f689307bf96b5978aff82b05536a4e90f022ab' 
  AND token = 'JuDqyz5cTFhsPQboh0V2BQKHEUK/8K9SWJhD21YtmZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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