SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cb63740f2ec21b125391465e0dda1fa0d8141a061f23238286abb903291d8c2' 
  AND token = 'iNvO/Z5mxTvWskCmTUALW+6HpcR3+SJ7v9hfLGbQARk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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