SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef6db0b0b9085f915eceb8ca9fa1f6ef5c5b272e48741c2551367bcbdf9b903a' 
  AND token = 'rsAnIrjyVM8nXbAhXjJ2B5wkXw7VmYvm46d76WQ8kPc=' 
  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"
    }
  }
}