SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6049d0622e227c82bba1732243e397f40f521db10622fbae8aa7977b9f9550a9' 
  AND token = 'CUY+SBXg9BWbZT5gc0UNlASAiJl93CJUXmZ7bAaalvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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