SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '242e27ea2df471bf172d14cc052170aaff43d4af24eea33a56621559bf434196' 
  AND token = 'Aeu3r2Tn4Z9Nrp1plLRPnARnJSg4y1fd2vOoHM/hyiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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