SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7954019f17600ee6dedb8807954e31ea975406ec025433f553235d312aa94c5' 
  AND token = '1fMLSzbGhhg8XwVoPuw7hymrLAxDMtHXplmE4ILwVcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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