SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a6a796442e8d278fd00c18dea7e49284e974eaf9e0a74b98535bc71b2b3c8a9' 
  AND token = 'WeMXVxZRhpRpeb9Gyk8GbtyN70l87Zd6o7PY+t5x3uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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