SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c39fc60ab80d4e8880479c303d269c8d231bd00ff55b88cd0c7272d5ca553160' 
  AND token = 'RDWfsX+h8T7jnZDVxVFfqCcyAnN0d+H2eCvpSBjsETE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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