SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1654889ff762a7a2a49fd4b762d5f43a0bc9a41b2f38bc8386331ca373669dc1' 
  AND token = '5rF1zuKXxJv5t6bOA5tKk1+Q8iVTwjYehM1C/lznERY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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