SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '814cbfac103ae0f31f006eed5be5adfbaa0f772e7e833692a65b42d7bb61834d' 
  AND token = 'r9HVvi023wUM80vZDcWXX6npRc7gz6dAl6IiZrRSRQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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