SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '536a8a132b1094ac281ccd60696d3b238987382d5bb0fcd82a27aa7cf2330380' 
  AND token = 'oLj9vkZtB0fmx/byEYA0RGsnWASNpM6Z7DBIJ96AAUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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