SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '510633759a518aa23899282e8b98bb1ed2a739ba84110eedd8c841a9df63adb6' 
  AND token = '+q/HG9AlYcGPZegglpBI2ZWgsl47kyQYkKMuav+yuMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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