SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7285a99eb5772cee3ff55f404ff391fff3e4556a4821872f5c39c0deb152dad' 
  AND token = 'cpfZuXcmFgqoWXOzk9rZLiTQRHXw5axm4acjeDKTriQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}