SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca9bd7826075611208dfa6bfabcb1bd1e3779e0e761573bc83cea5544c7397f1' 
  AND token = 'znQdntvqm1AKEGoth8HV6LGmC68PvQLnlqcyXmysWhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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