SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3f97365b67a9d565288fbe41221b125cc9a1e54402d5c20c8f819580bf1bec1' 
  AND token = 'vZnysGJsEf9apCRuuFHJL/ELdYbUfhX+BCSQO0F3bbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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