SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3216c1328574cf4f842af680c73cb52b3caa185c29b3ffd6665871a940bcab0' 
  AND token = 'ibMGED8rizZzIwVlGuz5BN/7CLXtAfDk+MVjQi75j+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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