SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8207192ca47a28ffc484e44026022c47589ad1b6782fc20e9481115ff4301cf9' 
  AND token = 'pxMuToHgmrNZFtxvEIieXzqXs4KaCgJrifRj56jHpgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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