SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad76388376bf6375cddebe5a788f0b86626ae89cb1305349df99b88879a7abe3' 
  AND token = 'NLBg+LcPzUzzdJ2NY8GH5OZVf3juLH2RQ0xI1U9WEXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}