SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82b6fa10d2e5c51f8efae8985f3a5664a9d52e8381405e0ad5d5aa4ad997da7a' 
  AND token = 'gkBclNp5Yce0uW7P0Fps/2luV/7lXe7a4PQZ8+y7Aro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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