SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72f350281645a1ce521cfd891587f102f604dfa3c78f9982c0f61d817c7c6d65' 
  AND token = 'DkclrAV4UkZpKM/idmM/Wj/HhI6VJyXGexV7DqL46gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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