SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e88c92a9824674848144f32546768060313f3ef131b37da6fa195f66c0d90489' 
  AND token = 'NFrvI2Bgu44m1mWXeDZfviXWf+uzysrWRggJTT0qppE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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