SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b4014393ccea34a2fc3d18f1c395cfe993e019aa3460e7eb4be175dd1c123ed' 
  AND token = 'veeUn7eCCtErIDQz8uN5WCdVYTEAdWIFHdygtH3hfOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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