SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a2cd2977bcb250c6b8e78297dc9e8616410c739fa1144a719a4b9263968deca' 
  AND token = 'ewgPhPxOIfuhO68rMYjU26fBgqm5rObaDqgWTTdzVHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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