SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db538b7ce719b24f713f57da6796a08405361e9e039d8ecb8f836e4cc71a40ad' 
  AND token = '1j7DiFxByaOFQo11sYqDE5fB1nYryhYeEW63DqJQDyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}