SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fddc15d18e8a49346a1b705b91c9d28d42355d0df4bcee202040bfda7a4a542' 
  AND token = 'ka+AfHi1N3H6IdOpjKQ8+A6cIJ8wQfbDOHY7inEJFS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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