SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75275a4d823b2182dd330a8cbd0dc008fa381571b24e3346794b17359ee20129' 
  AND token = 'GcUbMCUA9IzDwvsbR5qEfVMWiUH7hpXOzaOpLNt+Q6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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