SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eb698761315b399cabc2765d406b049509aa5e7fb73cd181fe08285ee500b2b' 
  AND token = 'UXEcROh3Ldkus5yKJNDhPkYETWuulk/UlSRokUqhdiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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