SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d83360beee97b7998869c7b6a2419c7181b2809458bd32c6b792b84e589288c' 
  AND token = '7lVLxqDRpkYJmmz9WzahIjL6EuG24KwaAIZBxZ1SkRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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