SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bbc6c8288962c3ff9c746c7e6e1da6c6035306557ec55730fc7178efec025a3' 
  AND token = '1+7j/gAuZQPLHiPYziMoryqDBOwqDmVog+VDJKM16zQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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