SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad66dfd58c330c84dab35bd81f26ad18f13aeeb22dddd734447fb76c179e45d2' 
  AND token = 'a0DycAQMiV/IoeLM54YBm1Q+ua60SUWB5EoGs5zyO7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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