SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b09afa1545c36268a7cea1fe65e49ec3a9840bcb058c5774f0f60a7e483c13e' 
  AND token = '9dx+SMuk+mlFCf1cZt8KV9GVWUS82qbVadhIkaKdAFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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