SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bd8dfd3bf6a46d7c10e0fb5054eb868fd5be4da94b17f127ebdbc54c301bc3b' 
  AND token = 'rUFlfyeGvdAprIwscITUbg8/q9N16VnUwMk1Lx8ieV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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