SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '535c14aabb353ee0725eb2a8acc99a9231832cf7203b6ef7f18cfa760c3f9fb6' 
  AND token = 'US72Gl5L+QREjXFhZm3tNAbiKuKe/SZ0+DWdqpES1D0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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