SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bb082380734b552a4f6896cffd7914647fd2823847e0e9b9ad0a40767c40edd' 
  AND token = 'SPdth2//nsPevQGHaTMLAikZfwSGLJc7qu+XGj4jg7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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